Value exception for RDBMS interface.

I've searched the PI RDBMS interface documentation for everything exception related. I couldn't find an explanation on how that work... I made a point PI to get the current minute from an SQL server through a RDBMS PI interface. It work fine, i get my right values but i can't get the exception filtering to work.

The point get a value every 5 seconds (scan class). So the interface send 12 values of every minute to the snapshot. I set the ExcDev to 1 so i get only minutes changes (ex 11 to 12 at 10:12:03) but it doesnt stop the archive get all the values. I've tried different critéria, 0.5, 5, 10, no difference. On the other hand, the ExcMin and Max do work. I could filter a value every minutes by setting these to 1/2 with a ExcDev to 0...